Hello everyone-I am tethered to an iMac with a USB 3 cable to the Canon 5D Mark 4. Sometimes I get a block on the image as shown- other times, the connection is lost between Capture One 11 and the camera. If I try turning off the camera, the display says something about 'Recording' an image and never seems to end. So I turnoff the camera, remove the cable, sometimes restart the iMac and start all over. How can I get this all to behave?http://files.blackinc.net/purple.jpg